The lens within an eye focuses light onto the
a. pupil.
b. cornea.
c. retina.
d. iris

The correct answer is C) Retina.

The light enters eye through pupil ( a small black colored hole in the center of iris of the eye). The light is focussed onto retina ( a sensory membrane located at the back of the eye) with the help of cornea and eye lens.

Photoreceptor cells are present in the retina that converts the incoming light into electrical signals, which are finally sent to brain via optic nerve in order to from the visual image.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.

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